illustration (attribution, if any possible, is at the end of the article)

“How people treat you is their karma; how you react is yours.”
— Wayne W. Dyer

You'll experience what you set up in motion by your reaction: it's only causality, because the environment you shape is also the environment you live in!

Don't waste time to try and interpret a past you can't reliably remember. Focus on setting here&now a wholesome world in motion!
The teachings on karma are not to second-guess what caused what, they are about how you act here&now!

Your tendencies, volitions and desires will have consequences… You cannot have these tendencies, volitions and desires without their consequences. This would be enjoying an 'independent' self separable (on demand) from the causal web, but you don't have such a self…

Which tendencies, volitions and desires will you nurture?
Well… what consequences do you want to experience?
You have intelligence and wisdom: use them!